The major overall objectives of this project are 1) to determine the molecular profile of human melanoma associated antigens with particular emphasis on the chemical structure of their antigenic sites, 2) to elucidate mechanisms of antigen transport, expression and shedding with emphasis on the role played by carbohydrate, and 3) to assess the feasibility of detecting antigens shed from malignant melanoma cells into the circulation which correlate with tumor growth in an animal model system. To attain these major objectives, melanoma associated antigens are isolated and highly purified by immunochemical techniques utilizing monoclonal antibodies. Emphasis is placed on obtaining protease-derived fragments of melanoma associated antigens still retaining their antigenic reactivity and on thoroughly characterizing them by chemical means to assess the molecular nature of their antigenic site(s). In vitro translation of melanoma associated antigens in the absence of glycosylation serves to delineate the role of carbohydrate in affecting antigenic structures while inhibitors of N-glycosylation are used to elucidate the role of carbohydrate in mechanisms governing antigen transport, expression and shedding. It is anticipated that results obtained from the proposed studies will aid in gaining an understanding of the molecular basis underlying functional changes of malignant cells, particularly molecular mechanisms involved in the interaction of tumor cells with the host's immune system. Research designed to determine in an animal model system whether it is possible to correlate tumor growth with the shedding of tumor antigens into the circulation should make it possible to critically assess the utility of such antigenic markers for the detection and prognosis of human cancer.